Document Type

Conference Paper

Publication Date


Publication Details

Jessica Juric and Russell Thomas, Development of a Protodyakonov test from gas drainage core samples and empirical correlation to observed outburst risk, Proceedings of the 2024 Resource Operators Conference, University of Wollongong - Mining Engineering, February 2024, 212-228.


Given the recent interest within the Australian coal industry around the use of Protodyakonov Index as means to assess outburst probability, a method to test core samples retrieved by underground inseam drilling was developed, and results compared to development experience in an Australian mine that has had outbursts during remote mining above outburst threshold. The dataset included a large number of core samples and lump samples from outbursts that occurred under remote mining at an Australian underground coal mine. This provides a unique data set from Australian conditions, the authors are unaware of other datasets including both a large number of samples and samples taken from the site of actual outbursts in Australian conditions with Protodyakonov Index values. A number of variables were found to affect the results reported, including some artifacts from lab testing processes, core recovery processes, and some that are known to impact outburst risk. Based on these results, a linear outburst probability model was developed. This indicates that changes in Protodyakonov Index in areas adjacent to geological structure and gas content above outburst threshold has a significant impact on outburst probability. The results of this analysis indicate that if all else is kept constant, then for the mine that was studied, a Protodyakonov Index value less than approximately 0.6 mean that an outburst is highly likely when close to geological structure and gas content is above outburst threshold. Between approximately 0.6 and 1.4, when close to a geological structure and above outburst threshold gas content, there is a statistically significant outburst probability, with the probability highest at lower values of Protodyakonov Index. The analysis highlights the importance of a thorough knowledge of the geology of an area to be mined, but does present an additional means to help assess the outburst risk of a geological structure. It is emphasised that this should only be applied as part of a broad consideration of multiple factors, and not simply applied as a pass/fail against a critical value.